Ice cube tray evaporator

ABSTRACT

An ice cube tray evaporator ( 10 ) includes a back plate ( 12 ) and a grid ( 14 ) of rectangular-shaped ice cube forming compartments ( 16 ) on the back plate ( 12 ). Each of the compartments ( 16 ) is defined by a back wall ( 18 ), and four side walls ( 20,22,24,26 ), with two of the side walls ( 20,22 ) being defined by parallel microchannel tube legs ( 28 ) spaced opposite from each other and the other two of the side walls ( 24,26 ) being defined by heat conductive strips ( 30 ).

CROSS-REFERENCE TO RELATED APPLICATIONS

Not Applicable.

FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable.

MICROFICHE/COPYRIGHT REFERENCE

Not Applicable.

FIELD OF THE INVENTION

This invention relates to evaporators that are utilized in making ice cubes.

BACKGROUND OF THE INVENTION

Ice machines for ice cube producing are known to utilize ice cube forming trays wherein a grid of ice cube forming compartments is cooled by a back plate having an evaporator coil either attached to the back plate or formed as an integral part of the back plate. In some typical applications, a copper tube evaporator is brazed to a copper back plate and then the entire tray is nickel-plated. The tray is installed in a vertical orientation so that water flows down the front in a waterfall effect with the water freezing in the compartments as it flows through them. A defrost cycle releases the frozen ice cubes from the compartments, which may have a slight angle, such as 15° from perpendicular to vertical, so that the ice cubes slide out of the compartments under the force of gravity. While such constructions may be suitable for their intended purpose, there is always room for improvement.

SUMMARY OF THE INVENTION

In accordance with one feature of the invention, an ice cube tray evaporator includes a grid of ice cube forming compartments, with each compartment defined by a back wall and four side walls, and two of the side walls defined by microchannel tube legs spaced opposite from each other.

As one feature, the back wall of each compartment is defined by a microchannel tube.

In accordance with one feature of the invention, an ice cube tray evaporator includes a back plate; and a grid of ice cube forming compartments on the back plate. Each compartment is defined by the back plate and four side walls, with two of the side walls being defined by microchannel tube legs spaced opposite from each other.

In one feature, the ice cube tray evaporator further includes a pair of parallel, spaced headers and a plurality of parallel, spaced microchannel tubes extending between the headers with ends of the tubes received in the headers for the transfer of refrigerant between the tubes and the headers. Each of the tubes defines one of the microchannel tube legs. According to a further feature, each of the headers extends along a longitudinal axis and includes a plurality of spaced, elongate tube receiving slots, with each slot receiving an end of the microchannel tubes. The slots are formed at a non-perpendicular angle with the longitudinal axis of the header, and the side walls share the non-perpendicular angle to allow for gravity assisted ejection of the cubes from the compartments with the longitudinal axis extending in a vertical direction.

According to one feature, the ice cube tray evaporator further includes a microchannel tube extending in a serpentine shape to define the microchannel tube legs of the grid. As a further feature, the ice cube tray evaporator further includes an inlet manifold connected to one end of the microchannel tube to deliver refrigerant thereto, and an outlet manifold connected to the other end of the microchannel tube to receive refrigerant therefrom.

In accordance with one feature, the other two side walls of each compartment are defined by elongate strips of heat conductive material.

As one feature, the microchannel tube legs and the back wall are made of aluminum material. As a further feature, the microchannel tube legs and the back wall are plated with nickel.

In one feature, the microchannel tube legs are brazed to the back wall.

According to one feature, the grid is a first grid of ice cube forming compartments, and the ice cube tray evaporator further includes a second grid of ice cube forming compartments, with the first and second grids facing in opposite directions in a back-to-back configuration.

In accordance with one feature, the back plate is a microchannel tube.

As one feature, the microchannel tube legs are brazed to the back wall.

In accordance with one feature of the invention, a method is provided for making an ice cube tray evaporator. The method includes the step of brazing a plurality of spaced, microchannel tube legs to a back plate to form a grid of ice cube forming compartments having the tube legs as side wall.

In one feature, the brazing step is an aluminum brazing step.

According to one feature, the brazing step includes brazing a pair of elongate, parallel spaced headers to ends of each of the tube legs.

As one feature, the method further includes the step of forming an elongate microchannel tube into a serpentine configuration to define the tube legs of the grid prior to the step of brazing.

In accordance with one feature, the method further includes the step of nickel plating the tube legs and back plate after the step of brazing.

Additional objects and/or features of the invention can best be understood by a detailed reading of the entire specification, including the appended claims and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an ice cube tray evaporator embodying the present invention;

FIG. 2 is an exploded view of the ice cube tray evaporator of FIG. 1;

FIGS. 3-7 are perspective views showing alternate embodiments of ice cube tray evaporators embodying the present invention; and

FIG. 8 is a section view of a microchannel tube that can be utilized in each of the embodiments of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference to FIGS. 1 and 2, an ice cube tray evaporator 10 includes a back plate 12 and a grid 14 of rectangular-shaped ice cube forming compartments 16 on the back plate 12. Each of the compartments 16 is defined by a back wall 18 (the portion of the back plate underlying the compartment 16), and four side walls 20, 22, 24 and 26, with two of the side walls 20 and 22 being defined by parallel microchannel tube legs 28 spaced opposite from each other and the other two of the side walls 24 and 26 being defined by heat conductive strips 30. Each of the strips 30 has a plurality of tube leg-receiving slots 31 that allow the strip to be assembled onto the tube legs 28. In this regard, it is preferred that each of the slots closely conform to the exterior shape of the corresponding tube leg 28.

In the embodiment of FIGS. 1 and 2, the ice cube tray evaporator 10 includes a pair of parallel spaced headers 32 and 34, and each of the microchannel tube legs 28 is defined by one of a plurality of parallel spaced microchannel tubes 36 extending between the headers 32 and 34, with ends 38 of the tubes 36 being received in corresponding elongate tube slots 40 formed in the headers 32 and 34 for the transfer of refrigerant between the tubes 36 and the headers 32 and 34. As best seen in FIG. 2, each of the headers 32,34 extends along a longitudinal axis 42, and preferably each of the elongate tube receiving slots 40 is formed at a nonperpendicular angle (15° from perpendicular in the illustrated embodiment) with the longitudinal axis 40 of the header, which positions each of the tubes 36 and corresponding side walls 20 and 22 at the same nonperpendicular angle to allow for gravity assisted ejection of the ice cubes from the compartments 16 when the longitudinal axis 42 extends in a vertical direction and the tube legs 28 extend in a horizontal direction. The headers 32,34 include inlet or outlet ports 50 and 52 and end caps 54, all of which can be of any suitable construction.

FIG. 3 shows an alternate embodiment of the ice cube tray evaporator 10 that differs from the embodiment 10 of FIGS. 1 and 2 in that it is designed so that the tubes 36 and corresponding side walls 20 and 22 and tube legs 28 extend vertically, rather than horizontally. In this regard, it is preferred that the strips have a nonperpendicular angle with the vertical axis (15° from perpendicular in the illustrated embodiment), rather than the tubes 36 and associated tube slots 40 in the headers which can be perpendicular to the axis 42 in the embodiment of FIG. 3.

FIG. 4 shows yet another embodiment of the ice cube tray evaporator 10 similar to the embodiment of FIG. 3, except the microchannel tube legs 28 are defined by a continuous microchannel tube 54 that has been shaped into a serpentine pattern, rather than individual tubes 36 as in FIG. 3, and the headers 50 and 52 are replaced by manifolds 56 and 58 provided at each end of the tube 54 to direct refrigerant to and from the tube 54. In the illustrated embodiment, the tube legs 28 are intended to extend in the vertical direction with the strips 30 having the nonperpendicular angle (15° from perpendicular in the illustrated embodiment) with the vertical direction in the same fashion as the embodiment of FIG. 3.

FIG. 5 shows yet another embodiment of the ice cube tray evaporator 10 that is similar to the embodiment of FIG. 3, except that the back plate 12 is provided in the form of one large microchannel tube 60 that is supplied refrigerant by a pair of spaced elongate headers 62 and 64 having inlet and outlet ports 66 and 68 similar to the ports 50 and 52.

FIG. 6 shows another embodiment of the ice cube tray evaporator 10 that is similar to the embodiment of FIG. 4 except for the provision of another grid 70 of ice cube forming compartments 16 that is provided on an opposite side of the back plate 12 from the grid 14 so that the grids 14 and 70 face opposite directions in a back-to-back configuration. The grid 70 is formed using another one of the serpentine tubes 54, with the additional tube 54 being fed by the manifolds 56 and 58.

FIG. 7 shows an embodiment having an additional grid 72 similar to the embodiment of FIG. 6, but formed of the parallel tube-type construction of FIG. 3.

It should be understood that in each of the embodiments of FIGS. 1, 4, 6 and 7, the back plate 12 could be provided in the form of a large microchannel tube similar to the embodiment of FIG. 5.

As another option for the embodiments of FIGS. 1-3, 5 and 7, one or more baffles can be inserted into the headers 32 and 34 to provide multi-passing of the refrigerant through banks of the tubes 36.

FIG. 8 is a somewhat diagrammatic view of a cross section of a microchannel tube 73, as could be used for the tube legs 28 or the back plate 12, and illustrates that the tube has an essentially flat cross section with a plurality of microchannels or ports 74 extending in the longitudinal direction. It should be understood that are a number of possible configurations for the ports 74 and that the particular configuration shown will be highly dependent upon the requirements of each application. It should also be understood that in embodiments that incorporate a microchannel tube in the back plate 12, the ports 74 in the back plate 12 may be of a different configuration than the ports 74 of the microchannel tube legs 28. Furthermore, it may be desirable in some applications to vary the port configurations from microchannel tube leg 28 to microchannel tube leg 28, or even potentially within a microchannel tube leg 28.

While any suitable materials can be used for the components of the above-described ice cube tray evaporators 10, aluminum is a preferred material, with all of the joints being braze joints that are formed in a single oven braze operation. In this regard, it may be desirable for some or all of the components, such as the headers, tube legs, or strips, to be formed of an aluminum braze clad material to assist in the brazing. It is preferred that the microchannel tube legs 28 be brazed to the back plate 12, and the same holds true for the strips 30. After brazing, the ice cube tray evaporator 10 can be nickel-plated to meet FDA regulations for pottable water and ice making.

It should be appreciated that the disclosed ice cube tray evaporators 10 can provide a construction that is relatively easy to manufacture, and when made from aluminum, a construction that can easily have a lower cost than current technology ice cube tray evaporators made from copper. Additionally, it should also be appreciated that the use of microchannel tubes can allow for the ice cube tray evaporator 10 to be used with higher pressure systems such as CO₂ systems, as well as with more conventional lower pressure systems, thereby allowing the ice cube tray evaporators 10 to be used with a larger variety of refrigerants in comparison to conventional constructions. It should also be appreciated that the use of microchannel tubes can also reduce the internal volume of the ice cube tray evaporators 10 in comparison to current technology ice cube tray evaporators, thereby reducing the cost of refrigerant to fill the system and some potential risk associated with flammable refrigerants. Also, the use of microchannel tubes can provide quicker cycle times, which include freezing of water in a shortened defrost cycle to remove the ice cubes, in comparison to conventional ice cube tray evaporators. 

1. An ice cube tray evaporator comprising a grid of ice cube forming compartments, each compartment defined by a back wall and four side walls, two of the side walls defined by microchannel tube legs spaced opposite from each other.
 2. The ice cube tray evaporator of claim 1 further comprising a pair of parallel, spaced headers and a plurality of parallel, spaced microchannel tubes extending between the headers with ends of the tubes received in said headers for the transfer of refrigerant between the tubes and the headers, each of the tubes defining one of the microchannel tube legs.
 3. The ice cube tray evaporator of claim 2 wherein each of the headers extends along a longitudinal axis and comprises a plurality of spaced, elongate tube receiving slots, each slot receiving an end of the microchannel tubes, the slots formed at a non-perpendicular angle with the longitudinal axis of the header, said side walls sharing the non-perpendicular angle to allow for gravity assisted ejection of the cubes from the compartments with the longitudinal axis extending in a vertical direction.
 4. The ice cube tray evaporator of claim 1 further comprising a microchannel tube extending in a serpentine shape to define the microchannel tube legs of the grid.
 5. The ice cube tray evaporator of claim 4 further comprising an inlet manifold connected to one end of the microchannel tube to deliver refrigerant thereto, and an outlet manifold connected to the other end of the microchannel tube to receive refrigerant therefrom.
 6. The ice cube tray of claim 1 wherein the other two side walls of each compartment are defined by elongate strips of heat conductive material.
 7. The ice cube tray evaporator of claim 1 wherein the microchannel tube legs and the back wall are made of aluminum material.
 8. The ice cube tray evaporator of claim 7 wherein the microchannel tube legs and the back wall are plated with nickel.
 9. The ice cube tray evaporator of claim 8 wherein the microchannel tube legs are brazed to the back wall.
 10. The ice cube tray evaporator of claim 1 wherein the back wall of each compartment is defined by a microchannel tube.
 11. The ice cube tray evaporator of claim 1 wherein said grid is a first grid of ice cube forming compartments, and further comprising a second grid of ice cube forming compartments, the first and second grids facing in opposite directions in a back-to-back configuration.
 12. An ice cube tray evaporator comprising: a back plate; and a grid of ice cube forming compartments on the back plate, each compartment defined by the back plate and four side walls, two of the side walls defined by microchannel tube legs spaced opposite from each other.
 13. The ice cube tray evaporator of claim 12 wherein the back plate is a microchannel tube.
 14. The ice cube tray evaporator of claim 13 further comprising a pair of parallel, spaced headers and a plurality of parallel, spaced microchannel tubes extending between the headers with ends of the tubes received in said headers for the transfer of refrigerant between the tubes and the headers, each of the tubes defining one of the microchannel tube legs.
 15. The ice cube tray evaporator of claim 14 wherein each of the headers extends along a longitudinal axis and comprises a plurality of spaced, elongate tube receiving slots, each slot receiving an end of the microchannel tubes, the slots formed at a non-perpendicular angle with the longitudinal axis of the header, said side walls sharing the non-perpendicular angle to allow for gravity assisted ejection of the cubes from the compartments with the longitudinal axis extending in a vertical direction.
 16. The ice cube tray evaporator of claim 14 further comprising a microchannel tube extending in a serpentine shape to define the microchannel tube legs of the grid.
 17. The ice cube tray evaporator of claim 16 further comprising an inlet manifold connected to one end of the microchannel tube to deliver refrigerant thereto, and an outlet manifold connected to the other end of the microchannel tube to receive refrigerant therefrom.
 18. The ice cube tray of claim 13 wherein the other two side walls of each compartment are defined by elongate strips of heat conductive material.
 19. The ice cube tray evaporator of claim 13 wherein the microchannel tube legs and the back wall are made of aluminum material.
 20. The ice cube tray evaporator of claim 19 wherein the microchannel tube legs and the back wall are plated with nickel.
 21. The ice cube tray evaporator of claim 20 wherein the microchannel tube legs are brazed to the back wall.
 22. The ice cube tray evaporator of claim 13 wherein said grid is a first grid of ice cube forming compartments, and further comprising a second grid of ice cube forming compartments, the first and second grids facing in opposite directions in a back-to-back configuration.
 23. A method of making an ice cube tray evaporator, the method comprising the step of brazing a plurality of spaced, microchannel tube legs to a back plate to form a grid of ice cube forming compartments having the tube legs as side wall.
 24. The method of claim 23 wherein the brazing step is an aluminum brazing step.
 25. The method of claim 23 wherein the brazing step includes brazing a pair of elongate, parallel spaced headers to ends of each of said tube legs.
 26. The method of claim 23 further comprising the step of forming an elongate microchannel tube into a serpentine configuration to define the tube legs of the grid prior to the step of brazing.
 27. The method of claim 23 further comprising the step of nickel plating the tube legs and back plate after the step of brazing. 